Sentence 1 says "it advocated a conservative approach". The pronoun "it" refers to the "consumer welfare standard" mentioned in 4. Thus 41 forms a pair. Though subtle, the connection between 1 and 2 can be easily established. Many industries gained market share because of conservative approach to antitrust enforcement (you can check the meaning of antitrust enforcement laws). Thus 1 is the cause and 2 is an effect. 3 is an example of that wherein we have the examples of technology companies such as Google, Facebook and Amazon which have benefitted immensely from dearth of enforcement actions. Thus 4123 is the right sequence.